Strumigenys mediocris, Tang & Guénard, 2023

Tang, Kit Lam & Guénard, Benoit, 2023, Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species, European Journal of Taxonomy 907, pp. 1-144 : 87-90

Strumigenys mediocris sp. nov.

urn:lsid:zoobank.org:act:B3C1039A-2E37-4102-97C9-BCB2B7D69C54

Fig. 29 ; Table 2

Diagnosis

Strumigenys mediocris sp. nov. can be distinguished from other species in the S. godeffroyi -group by a combination of the following characters: apicoscrobal seta simple; pronotal humeral seta flagellate; pronotum and dorsum of petiolar node fully sculptured; pleurae, side of propodeum and disc of postpetiole mostly smooth and shining; propodeal spines subtended by narrow lamellae; petiolar node with differentiated anterior face, not claviform; gastral tergites with long erect simple setae; dorsal surface of femur with erect setae; hind tibiae and basitarsi with long projecting flagellate setae; SI 85–88.

Etymology

The species is named after its ordinary morphology. The epithet ‘ mediocris ’ is the nominative feminine singular of the Latin adjective ‘ mediocris ’ (meaning ‘ordinary’).

Type material

Holotype worker ( Fig. 29 )

MAINLAND CHINA • Hainan Province, Bawangling , BWLP1; 19.11618° N, 109.15523° E; 29 Jun. 2016; L. Wang leg.; Winkler, 12 random; primary forest; LKCNHM ANTWEB1011879 (collection code IBBL HNA-00988).

Paratype workers

MAINLAND CHINA • 2 workers; same collection data as for holotype; HKBM ANTWEB1011915 to ANTWEB1011916 (collection code IBBL HNA-00988) .

Additional material examined

MAINLAND CHINA – Hainan Province • 2 queens; Bawangling, BWLP6; 19.09148° N, 109.20041° E; 1 Jul. 2016; L. Wang leg.; Winkler, 4 corners; IBBL ANTWEB1011878 , ANTWEB1011914 • 1 worker; Bawangling, BWLP9; 19.0903° N, 109.20101° E; 3 Jul. 2016; L. Wang leg.; Winkler, 12 random; IBBL ANTWEB1011880 .

Measurements

Holotype worker

TL 2.7, HL 0.64, HW 0.46, MandL 0.31, SL 0.41, EL 0.061, PW 0.24, ML 0.68, PL 0.34, PH 0.14, DPW 0.10, PPL 0.17, GL 0.60, CI 72, MI 48, SI 88, OI 13, LPI 42, DPI 30.

Paratype workers

TL 2.7–2.8, HL 0.62–0.64, HW 0.45, MandL 0.30–0.31, SL 0.39, EL 0.055 –0.063, PW 0.25–0.26, ML 0.66–0.72, PL 0.30–0.31, PH 0.12–0.13, DPW 0.10–0.12, PPL 0.16–0.19, GL 0.61–0.62, CI 70–73, MI 47–50, SI 85–87, OI 12–14, LPI 40–41, DPI 32–38 (n= 2).

Worker description

HEAD. In full-face view, occipital margin evenly, deeply concave; occipital corners well developed; preocular lamina wide; posterior clypeal margin well defined, converged at midpoint to form right angle (or just slightly smaller than a right angle); anterior clypeal margin very broadly, shallowly concave. Scapes subcylindrical, marginated but not converging anteriorly to form thin lamella at leading edge; apical antennomere unconstricted basally. Mandible curvilinear and long, with spiniform preapical tooth located close to apicodorsal tooth; width of mandible fairly constant from basal portion to where preapical tooth first arises; the preapical tooth in length at least 1.5 times width of mandible at point where tooth arises; apicodorsal tooth markedly longer than apicoventral tooth. In profile view, eye with three ommatidia in diameter.

MESOSOMA. In profile view, promesonotal dorsum convex, propodeum more or less flat transversely; pronotum not marginated dorsolaterally. In dorsal view, lateral margins of pronotum broadly convex. Propodeal teeth short and triangular, subtended on each side by narrow lamella with mostly transverse posterior margin, roughly parallel with margin of declivity. Metapleural gland bulla well developed.

METASOMA. In profile view, petiole not claviform; petiolar node with anterior face differentiated from peduncle, petiolar peduncle slightly longer than node, around 1.1–1.2 times as long. In dorsal view, petiolar node slightly broader than long, around 1.2–1.3 times as long; disc of postpetiole broader than long, around 1.4–1.6 times as long. Areolate processes (spongiform tissues) present on both petiole and postpetiole; ventral lobes of petiole and postpetiole extensive; lateral lobe of petiole merely a flap at posterolateral angle of node in profile; anterior face of node with inconspicuous strip; in dorsal view, processes present along posterior margin of petiolar node, and surrounding disc of postpetiole, thicker along lateral and posterior margins than on anterior margin.

PILOSITY. In full-face view, cephalic dorsum only with handful of appressed setae close to clypeus; apicoscrobal seta simple, stout and straight; around 3–4 shorter setae present posterior to it on lateral margin of occipital lobe. Antennae and mandibles covered with short appressed simple setae; upper scrobe margin with short suberect seta, stout to acicular and slightly curved; lateral clypeal margins, leading and trailing edges of scape with suberect to decumbent stout setae; those on edges of scape apically directed; anterior clypeal margin with medially-directed acicular setae. Pronotal humeral seta long and flagellate. In profile view, cephalic dorsum, mesosomal dorsum, dorsum of petiolar node and disc of postpetiole with simple erect simple setae; those on cephalic dorsum denser than rest of body; petiolar node and disc of postpetiole also with posteriorly-directed decumbent simple setae; gastral tergites with numerous long erect simple setae; ventral surface of head with short decumbent setae; gastral sternites with short suberect simple setae. Hairwheel present at mesopleural excavation. Dorsal surface of femur with row of long fine erect setae against ground pilosity of appressed setae; surfaces of middle and hind tibiae and basitarsi with long projecting flagellate setae.

SCULPTURE. Surface of head (including antennal scrobe), antennae, side of pronotum, mesosomal dorsum, petiolar node and legs densely areolate; mandibles with sparse weak punctate sculpture and weakly areolate basally, but otherwise mostly smooth. Pleurae, side of propodeum and disc of postpetiole mostly smooth and shining, with vestiges of sculpture around margins. Basigastral costulae short, around one fourth in length of first gastral tergite; rest of gaster smooth and shining.

Comments

Strumigenys mediocris sp. nov. is a member of Subgroup A in the S. godeffroyi -group and shares all its characters ( Bolton 2000), and could be assigned to the smythiesii -complex, which accommodates species that do not belong to the godeffroyi -complex or the mjoebergi -complex. Strumigenys mediocris does not belong to the godeffroyi -complex as it does not have an extensive lateral lobe of the petiole, and its apicoscrobal seta is simple (instead of flagellate). It does not belong to the mjoebergi -complex, for its pleurae and side of propodeum are smooth and shining (instead of reticulate-punctate), and it has long erect setae on the dorsal surface of the hind femur.

Aside from Strumigenys mediocris sp. nov., there are eight other species in the smythiesii -complex that either also have a simple apicoscrobal seta ( S. chernovi , S. hastur , S. hispida , S. jepsoni Mann, 1921 , S. lichiaensis , S. liukueiensis Terayama & Kubota, 1989 and S. solifontis Brown, 1949 ) or unknown ( S. choii ) ( Table 7 ). For S. mediocris , its pronotal humeral seta is flagellate (instead of simple as in S. hispida , S. jepsoni , S. liukueiensis or S. solifontis ); setae on promesonotal dorsum and gastral tergites are simple (instead of spatulatiform as in S. choii or S. lichiaensis , or subflagellate to flagellate as in S. hispida or S. liukueiensis ); the pronotal dorsum is sculptured (unlike S. choii or S. hastur ); the dorsum of the petiolar node is sculptured (unlike S. choii , S. hastur or S. jepsoni ); the disc of the postpetiole is smooth and shining (unlike S. chernovi ). Strumigenys mediocris also has a relatively shorter scape (SI 85–88) than S. lichiaensis (SI 98) or S. trada (SI 100).

Geographic range

Mainland China (Hainan).

Ecology

Collected in primary forest.

Figures

Fig. 29. Holotype worker (ANTWEB1011879) of Strumigenys mediocris sp. nov. A. Full-face view. B. Profile view. C. Dorsal view.